Tired of FDM 3D printers? Engineer constructs his own SLS 3D printer

Oct. 7, 2014 | By Alec

First of all, this isn't a critique of FDM 3D printers, which are wonderful machines for anyone looking for a creative outlet. However, it's indisputable that industrial Selective Laser Sintering (SLS) 3D printers are in a league of their own when it comes to high-quality results. For those of you who don't know, SLS 3D printers avoid extrusion printing entirely, and instead create objects selectively solidifying very fine powder materials using a laser.

And obviously this makes them way out of most people's leagues; SLS 3D printers can cost up to and over $1 million, while even the 'budget' versions can cost you as much as $100,000. While some initiatives have been started to make this technology available for a few thousand dollars, nothing has yet completely materialized.

But there is one exception that last remark, as the California-based engineer Brandon Fosdick has recently revealed the results of his efforts to construct his very own SLS 3D printer. While his SLS printer – affectionately named Ester – isn't quite at the mass-production stage, it nonetheless looks very promising and inspiring. He also hasn't provided a guide or tutorial that will allow you to make your very own version of Ester, but this prototype could very well hold the key to affordable SLS 3D printing technology in the near future.

Fosdick started this challenging project a few years ago and has been slowly modifying and improving the Ester ever since, up to a point where printing is actually become possible. This process took so long because there was very little information available about the basic mechanics of this technology, and so this software engineer had to teach himself the fundamentals about SLS printing. It's also the first printer Fosdick has ever assembled, so every step of the way was a learning experience.

As he explained in a thread on Reddit, the mechanics are a completely custom design, 'created by yours truly. It's mostly acrylic and aluminum extrusion. The controller board is a Frankenstein of a Smoothieboard, an LED driver demo board, a breadboard and a real laser driver. It's a dangerous mess.'

Because of his step-by-step learning and building process, the 3D printer also operates with a cartesian stepper system (so an xyz movement system for the laser head) that many FDM printers also use, rather than a galvanometer system (like a scanner) that many industrial SLS printers use.

As he explained, this was simply the result of the limited time, funds and knowledge he had during the building process:

I'd love to use a galvanometer-style system, but it's a bit more work to get it going, and there are still some patent issues with it. I haven't looked into it enough to know if the patents are prohibitive, or easily avoided, but I remember finding several that looked intimidating when I first started researching this project.

Another feature that emphasizes his step-by-step building process is the open topped nature, which can be a bit problematic as the powdery printing material has a tendency to go everywhere, including in your lungs. Fosdick explained that he does intend to add a complete enclosure if he decides to take this to a production level. For now, wearing a respirator is an absolute necessity, while the power can also irritate the skin.

The open-topped printing process is clearly visible in this YouTube clip of the printer in action:

Explaining the open-topped nature, he wrote:

I made it open so I can tinker with it, and because it was easier that way. While that's certainly been a convenient choice during development, the downside is that I can't run the A/C or have a window open while it's printing. Even the slightest little breeze sends powder everywhere. Some days I end up looking like a coal miner. Any sort of production version will most definitely have a full enclosure.

However, development has now reached a stage where objects can actually be made, and he posted several results on Reddit. But the prints are not quite perfect yet – 'The parts aren't very strong' – as the hardware can cause a bit of crumbling at times. For now, Fosdick is still trying to determine the most effective settings for each material. Nonetheless, Ester's results are very impressive for a home-made 3D printer.

Crumbled parts.

The current objects displayed are printed in a cheap polyester powder, commonly used for powder coating. He mainly used metal powders when first printing objects, but he quickly realized it would be much cheaper to limit himself to plastic and polyester. These cost about the same as filament for FDM printers, so about $25/lb and shipping. Copper, brass and aluminum are not terribly more expensive, though he suspects that 'the fancier stuff, like steel or titanium, is more expensive. I don't even want to guess at Inconel.' In time, however, the idea is that Ester can properly print using metal powders.

He's also working on increasing the printer's speed. 'The print speed was only about 50mm/s, so the gear took about 2 hours and the servo took about 6 hours. Now that I have it working I can start ramping up the speed. The gear was scaled down 50%, so it was about 30mm in diameter and 5mm thick. The servo is full sized, for a mini servo.'

After seeing this impressive, home-made construction, the obvious question on everyone's minds is 'what's next?' The development of Ester is still definitely a work-in-progress, but Fosdick hopes to be able to bring finished machines to the market. And fortunately, these would only cost a fraction of the price you'd be paying for industrial-grade SLS printers.

Speculating with another Redditor, Fosdick estimated that he could reach a break-even point somewhere between $2500 and $3000. 'And that's assuming I just do a kit; not a fully assembled version. To actually "kick start" a business I would need to do better than break even. Would people pay nearly $3000 for a kit?'

To reach this stage, however, he will likely need to start a Kickstarter crowdfunding campaign in the near future. This would allow him to fund the optimization of Ester's machinery and capacity, as well as construct a safe housing for the printing process.

While SLS 3D printers and building tutorials or kits are thus not quite available yet, Fosdick has done made some very promising, inspiring and wonderful steps. It's starting to look like this exciting 3D printing technology could become far more accessible and affordable in the near future. We'll be sure to keep you updated!